I Searched on this site and got the Cheapest Flight,Check it out,it also had Discount Coupon Codes for Expedia,Orbitz,Travelocity,Kayak, Priceline,etc.http://freetravel4ever.blogspot.com
there are quite a few sites that you can search that will likely give you the best prices available. check out the website BookMe and you will be able to compare prices on all the reputable travel sites in just a couple minutes. it s very convenient and will save you a bunch of time and money. Also, make sure you buy them online... otherwise they charge much higher fees for phone orders. good luck.
The answer before mine is a good one, just thought I d add that continental.com have some great deals and because their hub is Houston, you ll always have a flight going there. They re pretty reasonable for flights, but it all depends on the time of year you want to travel. Now is the most expensive time to want to fly anywhere.
I would check out Continental Airlines! They are by far my most favorite, and their main hub is for Houston (IAH), so they ALWAYS have cheap and frequent flights going to/from Houston-IAH.
Go to orbitz.com and cheaptickets,com and priceline.com and search, Be flexible as to dates and time of day. Try also southwestairlines.com
I can t believe no one mentioned Southwest Airlines. I prefer to fly Continental but if you re looking for cheap you can fly round trip for a couple hundred dollars sometimes.
I prefer Expedia to most of the others.
Good previous answers but I would add http://www.yapta.com to compare prices.